Which clematis pruning group do I have?

Every clematis pruning question comes down to whether it flowers on wood made last year or wood made this year, and the flowering month is a completely reliable proxy for that.

What you'll need

• Secateurs
• Plant label or a note of the flowering month (optional)

Step by step

1. Record when it flowers.Note the month on a label or your phone. If you do not know, leave the plant unpruned for a season and watch. One lost season is cheaper than cutting off two.
2. Identify group one.Flowers before May on last year's wood. Montana, alpina, macropetala, armandii and cirrhosa. Very vigorous in the case of montana.
3. Prune group one barely at all.Immediately after flowering, cut back only what has outgrown its space or is tangled and dead. Pruning it in winter removes the flowers.
4. Identify group two.Large flowers in May and June on last year's wood, often with a smaller second flush in late summer. Most of the big-flowered named hybrids — 'Nelly Moser', 'The President', 'Multi Blue' — are here.
5. Prune group two lightly in late winter.February. On each stem, work down from the top removing dead and weak growth until you reach a strong pair of fat buds, and cut just above them. That is all.
6. Identify group three.Flowers from July onwards on growth made this year. Viticella, jackmanii, texensis, orientalis and the herbaceous types.
7. Prune group three hard in late winter.February, cut every stem down to a strong pair of buds roughly 200 to 300mm above the ground. It looks brutal and it is exactly right.
8. Use the safe default when you do not know.Prune lightly after the first flowering flush, as if it were group two. You will get flowers on almost any clematis and lose very little.
9. Mulch and feed after pruning.Clematis are hungry. A mulch of compost kept clear of the stems and a spring feed makes a substantial difference to flowering.
10. Keep the roots cool and shaded.Clematis want their heads in sun and their roots in shade. A slab, low planting or a mulch over the root area is the traditional and effective approach.

Tips

• The flowering month tells you the group. Nothing else is needed.
• If in doubt, prune lightly after the first flush — the safe default for all three groups.
• Write the month on a label. You will not remember next February.

Common mistakes

• Cutting a montana back hard in winter — It flowers on last year's wood, so a winter cut removes the entire display. Montana is pruned after flowering and only when it has outgrown its space.
• Leaving a group three clematis unpruned — It becomes a bare tangle with all the growth and flowers at the top and nothing at eye level. These types need cutting to near ground level every year.

If it doesn't work

Questions people ask